PROJECT SUMMARY/ABSTRACT This Academic-Industry Partnership, AIP, proposal (PAR-18-009) will develop and evaluate an innovative multi-modality breast imaging platform that performs simultaneous Microwave and Magnetic Resonance Imaging (sMMRI). It incorporates a multiple-principal-investigator (multi-PI) research plan and AIP governance structure that leverages expertise from Dartmouth, Dartmouth-Hitchcock, and Quality Electrodynamics (QED) in biomedical engineering, MRI and microwave physics, computational inversion and estimation, and breast radiology. Industry partner QED will apply its extensive experience in design and implementation of specialized MRI coils that will be fully integrated and compatible with Dartmouth?s microwave imaging (MI) electronics and in-bore antenna array. To date, we have demonstrated technical feasibility of sMMRI and have realized a prototype that has delivered the first successful clinical breast exams. While potential promise of sMMRI has been suggested, especially in terms of acquiring quantitatively-accurate spatial maps of tissue electrical properties (i.e. permittivity and conductivity), further technical innovations are needed and more experience with sMMRI, both technically and clinically, is required to develop the technology sufficiently for a full clinical evaluation. To advance and optimize sMMRI of the breast while also increasing our understanding of its clinical potential, we propose to (1) develop and integrate MRI (receive) coils with MI antenna arrays to optimize MRI and MI image quality, and breast coverage during an sMMRI clinical breast exam, (2) estimate breast tissue electrical properties from sMMRI data by encoding MRI anatomical priors into the 3D reconstruction process, and (3) complete phantom and clinical breast imaging experiments with sMMRI to evaluate and optimize the proposed technical developments, and to conduct a clinical study in women with undiagnosed breast abnormalities to test the hypothesis that sMMRI improves the specificity of breast MR alone. If the studies we propose are successful, we will have realized an innovative multi-modality breast imaging platform that is ready for involvement in larger statistically-powered clinical studies of its diagnostic performance in the future.